In the liquid chromatography analysis, a mobile phase into which a sample injected by an auto-sampler is pumped into an analysis column. The sample introduced into the analysis column is separated into all components included in the sample and then each of the components is identified by a detector.
In the conventional liquid chromatography analysis, a pipe connection joint used for inserting a pipe into the analysis column consists, in general, of a ferrule and a compression screw to press the ferrule against a support face of the analysis column. When a pressure of a liquid to be pumped is as high as 40 to 60 MPa, a pressing force is applied by the compression screw to the ferrule and the ferrule is pressed against the support face so tightly that an end portion of the ferrule deforms and that there is no gap left between the ferrule and the support face. As a result, the ferrule has a function of sealing the transferred liquid and holding the pipe.
In recent years, applying a higher pressure (higher than or equal to 100 MPa) than before is required to make the analysis process completed much quicker and enable more accurate separation. There is a risk for a configuration of a ferrule and a compression screw that the ferrule cannot hold the pipe so reliably that the pipe slips through the ferrule, due to using more highly pressurized liquid.